Biobased compositions from distillers&#39; dried grains with solubles and methods of making those

ABSTRACT

A composition and process of making the composition having a dried particulate by-product of starch fermentation of a grain to produce ethanol such as DDGS, and a polymerized polyurethane binder derived from a polyurethane prepolymer that is a reaction product of at least one polyol and at least one isocyanate. The by-product is present in the composition in an amount between about 20 and 90% by weight of the composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.60/750,099, filed Dec. 14, 2005 incorporated herein by reference in itsentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to the utilization of distillers' driedgrains as well as distillers' dried grains with solubles in findingvalue-added biobased materials.

(2) Description of the Related Art

In ethanol industries, corn is usually processed to prepare ethanol.Distillers' dried grains with solubles (DDGS) are coproducts from drymilling ethanol industries, containing about 27% protein. Corn glutenmeal (CGM) is a byproduct from wet milling ethanol industries,containing around 60% of protein. Currently, the two types ofcoproducts/byproducts are mainly consumed as livestock feeds. Recently,several attempts have been made in developing CGM-based material (Wu, Q.X; Sakabe, H; Isobe, S. Ind. Eng. Chem. Res. 42, 6765, 2003; Di Gioia,L.; Guilbert, S. J. Agric. Food Chem. 47, 1254, 1999). The research onDDGS-based biodegradable material is rarely reported. Compared with CGM,DDGS is difficult to be processed in an extruder due to low proteincontent. As per our knowledge DDGS is cheaper (˜$0.05/lb) than CGM(˜$0.3/lb), which attracts attention on DDGS-based new materials.Schilling et al. (Schilling, C. H; Tomasik, P; Karpovich, D. S; Hart, B;Shepardson, S; Garcha, J; Boettcher, P. T; J. Polym. Environ. 12 (4):257-264, 2004) have prepared DDGS/soy protein based material. Themaximum strength of such material was found to be 1.67 MPa. Suchstrength is quite low and thus unsuitable for many applications. Inaddition, the process cost seems quite high because of the use ofseveral chemicals in modifying DDGS.

Polyurethane (PU) has been used to modify paper (Lee S. H; Teramoto Y;Shiraishi N. J. Appl. Polym. Sci. 83 (7): 1482-1489, 2002) and starch(Cao, X. D; Zhang, L. N; Huang, J; Yang, G; Wang, Y. X. J. Appl. Polym.Sci. 90 (12), 3325-3332, 2003) in making tough material. The toughnessof pure corn protein increased sharply by incorporation of 10-30 wt % ofPU prepolymer (Wu, Q. X.; Yoshino, T.; Sakabe, H.; Zhang, H. K.; Isobe,S. Polymer 44, 3909-3919, 2003) indicating an important role of PU inmaking tougher material from brittle protein matrix. However in thisstudy, the processing was conducted in chemical solution, whichincreased the processing cost and was limited in practice. The researchusing PU prepolymer to prepare tough DDGS-PU composite is rarelyreported.

Polyester-based polyurethane can also be hydrolyzed into small moleculesin usage, and thus is considered as environmental-friendly material. Butpolyester polyol is expensive ($1.4/lb) (Information from Bayer PolymersLLC, in February. 2004 (e-mail communication)). The weight percentage ofPU should be controlled to a low level (<50%) to prepare low costmaterial. In this work, low quantity of polyester-based PU prepolymerwas synthesized and mixed with DDGS in the micro-extruder and theresulting extruded material was molded to prepare low cost, tough andwater resistant composite.

SUMMARY OF THE INVENTION

The present invention provides a composition which comprises: a driedparticulate by-product of starch fermentation of a grain to produceethanol; and a polymerized polyurethane binder derived from apolyurethane prepolymer comprising a reaction product of at least onepolyol and at least one isocyanate, the by-product being present in anamount between about 20 and 90% by weight of the composition. In furtherembodiments, the polyol is a plant oil-based polyol. In furtherembodiments, the plant oil-based polyol is selected from the groupconsisting of castor oil, soybean oil, rapeseed oil and mixturesthereof. In further embodiments, the isocyanate is a diisocyanateselected from the group consisting of 4,4′-methylenedi-p-phenyldiisocyanate (MDI), naphthalene 1,5-diisocyanate (NDI), toluenediisocyanate (TDI), hexamethylene diisocyanate (HDI), IPDI, H₁₂-MDI,tetramethylene diisocyanate, and mixtures thereof. In furtherembodiments, the by-product is derived from corn. In still furtherembodiments, the by-product is distiller's dried grains with solubles(DDGS). In further embodiments, the polyurethane prepolymer was formedin the presence of an organometallic or amine catalyst. In still furtherembodiments, the organometallic catalyst is selected from the groupconsisting of tin (II) 2-ethylhexanoate, tinbutyltin dilaurate, andstannous octoate. In further embodiments, the composition was extruded.In still further embodiments, the composition was rapidly extruded andthen molded under pressure at elevated temperatures. In furtherembodiments, the composition further comprises natural fibers andorgano-clay. In further embodiments, the natural fibers are corn fibers.

The present invention provides a process for producing the compositionas set forth in Claims 1, 2 or 4, which comprises extruding a mixture ofthe prepolymer and the by-product at a temperature between about 25° C.and 80° C. In further embodiments, the composition is molded underpressure at elevated temperatures between 80° C. and 150° C.

The present invention provides a process for producing a compositioncomprising: providing a polyurethane prepolymer comprising a reactionproduct of at least one polyol and at least one isocyanate; extruding amixture of the polyurethane prepolymer and a dried particulateby-product of starch fermentation of a grain to provide an extrudate;and molding the extrudate of step (b) to form the composition, whereinthe by-product is present in an amount between about 20 and 90% byweight of the composition. In further embodiments, the extrudate of step(b) is compression molded in step (d).

The present invention provides a composition produced by the process ofClaim 15. In further embodiments, the composition is formed as a productselected from the group consisting of a piece of furniture, a tray, asheet, and a container.

The present invention provides a process for producing a compositioncomprising: providing a polyurethane prepolymer comprising a reactionproduct of at least one polyol and at least one isocyanate; providingnatural fibers; extruding a mixture of the polyurethane prepolymer, thenatural fibers, and a dried particulate by-product of starchfermentation of a grain to provide an extrudate; and molding theextrudate of step (b) to form the composition, wherein the by-product ispresent in an amount between about 20 and 90% by weight of thecomposition. In further embodiments, the extrudate of step (b) iscompression molded in step (d). In further embodiments, the extrudate ofstep (b) is injection molded in step (d).

The present invention provides a composition produced by the process ofClaim 18. In further embodiments, the composition is formed as a productselected from the group consisting of a piece of furniture, a tray, asheet, and a container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a scheme illustrating the preparation of tough distillers'dried grains with solubles (DDGS)/polyurethane based composite. (MDI:4,4′-methylenedi-p-phenyl diisocyanate).

FIG. 2 illustrates the FTIR spectra of castor oil, MDI, and PUprepolymer.

FIG. 3 is a graph illustrating the DMA results for DP30.

FIG. 4A is an image of the DDGS-PU composite containing 44% of PU. FIG.4B illustrates an image and FIG. 4C illustrates a schematic diagram ofDDGS-PU container containing 30 wt % of polyurethane. Weight=107.8 g,Base length=210 mm, Base width=148 mm, Thickness of the wall=3.63 mm.

FIG. 5 illustrates a TGA diagram of DDGS, MCPU and DDGS/PU composites.

FIG. 6 is a scheme illustrating the preparation of tough and waterresistant DDGS/DDG-based Materials (MDI—4,4′-methylenediphenyldiisocyanate).

FIG. 7 illustrates the effects of RH % on the weight difference of thecomposites.

FIG. 8 illustrates the effects of RH % on the storage modulus at 25° C.for the composites

FIG. 9A and FIG. 9B illustrate images of (FIG. 9A): DDGS 75%-PU 25% and(FIG. 9B): DDGS 60%-CS 15%-PU 25% after buried in soil for one month.

DETAILED DESCRIPTION OF THE INVENTION

All patents, patent applications, government publications, governmentregulations, and literature references cited in this specification arehereby incorporated herein by reference in their entirety. In case ofconflict, the present description, including definitions, will control.

Preparation of biobased material from the byproduct/co-product of thedry milling corn ethanol industry e.g. distillers' dried grains withsolubles (DDGS) and biobased polyurethane. The resulting biobasedmaterial can contain as high as approximately seventy-five percent (75%)of inexpensive DDGS thus making the product commercially attractive.

The present invention provides a composition which comprises: (a) adried particulate by-product of starch fermentation of a grain toproduce ethanol; and (b) a polymerized polyurethane binder derived froma polyurethane prepolymer comprising a reaction product of at least onepolyol and at least one isocyanate, the by-product being present in anamount between about 20 and 90% by weight of the composition.

As used herein, the term “by-product of starch fermentation” as usedherein can refer to, but is not limited to, byproducts/coproducts of thecorn ethanol industry. Examples include distiller's dried grains withsolubles (DDGS) and distillers' dried grains (DDG). Other grains fromwhich the by-product is derived can include, but are not limited tosorghum (milo), wheat, or barley.

As used herein, the term “polyol” as used herein refers to any monomericor polymeric molecule with more than one hydroxyl functional groups. Insome embodiments, the polyol is biodegradable. In some preferredembodiments, the term “polyol” refers to plant derived oils such ascastor oil, soybean oil, and rapeseed oil, however the term is notlimited thereto.

As used herein, the term “isocyanate” as used herein refers to anyisocyante including, but not limited to aromatic, cycloaliphatic(alicyclic), and aliphatic isocyanates. The term includes diisocyanatessuch as 4,4′-methylenedi-p-phenyl diisocyanate (MDI), naphthalene1,5-diisocyanate (NDI), toluene diisocyanate (TDI), hexamethylenediisocyanate (HDI), isophorone diisocyanate (IPDI), methylenebis(p-cyclohexyl isocyanate) (H₁₂ MDI), and tetramethylene diisocyanate.

This is the first report on preparation of DDGS-based tough materialwith DDGS content of around 75%. The preliminary cost analysis taking into account the materials costs is quite encouraging. The current priceof castor oil is $675/ton ($0.31/lb)(http://www.ipex.gov.mz/precos_en.php3?en=1, access date: 2006-Dec.-04).The price of MDI is $1.1/lb(http://www.plasticsnews.com/subscriber/resin/price4.html, access date:2006-Dec.-04). PU price is 69/(50+69)×0.31 +50/(50+69)×1.1=$0.64/lb.

The materials' costs of the biobased DDGS-PU product containingapproximately 75% DDGS and approximately 25% polyurethane (PU);designated here as DP25, was found out to be approximately $0.20/lb. Thecost calculation is shown as follows: Material cost of DP25=PUcost×25%+DDGS cost×75%=$0.64/lb×25%+0.05×75%=$0.20/lb. Processing costis not included in this calculation.

The content of biobased material (DDGS and natural polyol) in thecomposite was found out to approximately 90%. Such calculation isrepresented as follows: Content of biobased material in DP25=DDGSpercentages+castor oil percentages=75%+castor oil percentage in PU×PUpercentages in DP25=75%+69/(69+50)×25%=75%+15%=90%.

Experimental.

Materials: Castor Oil, 4,4′-methylenedi-p-phenyl diisocyanate (MDI), andTin (II) 2-ethylhexanoate (95%), were purchased from Sigma-Aldrich FineChemicals, St. Louis, Mo. Distillers' dried grains with solubles (DDGS)of Michigan Ethanol, Caro, Mich. was used in this work.

Synthesis of PU prepolymer: The ratio of isocyanate/hydroxyl group(NCO/OH) was 2.0. Castor oil (69.0 g) and MDI (50.0 g) were added into a250 mL four-necked flask fitted with a thermometer, a stirrer, an inletand an outlet of dry nitrogen, and stirred at 80° C. The stirring speedwas 300 rpm. Then 30 min later, the temperature decreased to 30° C. and110 μL of Tin (II) 2-ethylhexanoate catalyst was introduced into theflask under dry nitrogen with a syringe. The reaction was carried out at30° C. for fifty minutes. The polyurethane prepolymer (PUP) was sealedin a glass bottle. The bottle was placed into a silica gel desiccatorand stored at −20° C. in a refrigerator. U.S. Pat. No. 6,359,023 toKluth et al., incorporated herein by reference in its entirety,describes polyurethane prepolymer containing NCO groups made fromisocyanates and polyols derived from natural oils.

Preparation of DDGS-PU composites: DDGS was milled into powder (297 μm)in a mill machine (Cyclone Sample Mill, UDY Corporation, Colo., USA).The powder was dried at 105° C. for four hours and stored in adesiccator for the following experiment. DDGS and polyurethaneprepolymer (PUP) were mixed in a beaker by use of a glass rod and thenfed into a micro-extruder (15 cm³ in volume capacity, DSM Research,Netherlands). Extrusion temperature was 50° C., speed was 50 rpm. Theextruded material (5.0 g) was compression-molded in acompression-molding machine (Carver Laboratory Press, Model M, Fred S.Carver Inc, Menomonee, Wis.) at 100° C. Rectangular mold dimension was1.0×60×70 mm³, molding force was 10 ton and time was ten minutes. Themold was cooled to below 40° C. by a water-cooling system at a rate of10° C./min. The molded sheet was cut into strips with dimension of:1.0×10×70 mm³. The strip-like samples were stored in a desiccator. Thesheets containing various PU contents (25%, 30%, 40% and 50%) wereprepared, and coded as DP25, DP30, DP40 and DP50 respectively. DP25represents sheet from DDGS/PU composite containing 25% of PU. As acontrol, PUP (polyurethane prepolymer) was exposed to ambient conditionsto be cured by moisture. One month later, the cured PUP wascompression-molded at 150° C., for 30 min to prepare thin sheets. Thismaterial was designated as “MCPU” to represent “MDI/castor oil basedpolyurethane”. The procedure for preparing tough DDGS/PU sheet isrepresented in FIG. 1.

Characterization.

Fourier transform infrared spectroscopy (FTIR): A FTIR spectrometer(Spectrum One, PerkinElmer, Massachusetts, USA) using an attenuatedtotal reflectance (ATR) cell at room temperature is used here forcharacterization studies. All the spectra were recorded at a resolutionof 2 cm⁻¹ with accumulation of 5 scans. Three duplications wereconducted.

Tensile Test: The tensile strength, percent (%) elongation and tensilemodulus of the samples were tested using an Instron tensile tester(Instron 5565, Instron Co., Massachusetts, USA) according toIS06239-1986 (E) with cross head speed of 50 mm min⁻¹. Toughness isdefined by the area under stress-strain curve and its unit is MPa(Zhang, J; Mungara, P; Jane, J. Polymer, 2001, 42, 2569).

Water Uptake Measurement: Sheets with a dimension of 1 mm×10 mm×100 mm,were dried in a desiccator for one month, then weighed (W_(d)) and thenimmersed in water. Two days later the wet samples were taken out anddried by use of paper towel and reweighed (W_(w)). The water uptake wascacluated using the following equation:Water uptake (%)=[(W_(w)−W_(d))/W_(d)]×100   (1)

Soxhlet Extraction: Sheets were dried at 100° C. for seventeen hours andweighed (W_(d)). The dried samples were extracted in a Soxhlet extractorusing toluene for twenty-four hours, then dried in air for eight hours,then in an oven at 70° C. for fifteen hours, and at 110° C. for fourhours and then weighed (W_(e)). The weight loss was calculated using thefollowing equation:Weight loss (%)=[(W _(d) −W _(e))/W _(d)]×100   (2)

The equation for calculating the reaction ratio of PUP is shown asfollows:Reaction ratio=[W _(L) /W _(I)]×100   (3)

where W_(L) is the weight of the PUP linked to DDGS and W_(I) is theweight of the PUP incorporated into DDGS. Four duplications were carriedout.

Dynamic Mechanical Analysis (DMA): The thermo-mechanical properties wereevaluated with a dynamic mechanical analyzer (DMA Q800, TA Instruments,Delaware, USA) in single cantilever mode. The DMA testings wereinvestigated from −120° C. to 140° C. at a heating rate of 3° C./min. Avariable-amplitude, sinusoidal tensile stress (frequency=1 Hz) wasapplied to the samples to produce a sinusoidal strain of ±30 μmamplitude. Two duplications were done.

Thermo Gravimetric Analysis (TGA): Testing was conducted using a thermalgravimetric analyzer (TGA 2950, TA Instruments, Delaware, USA).Approximately 10 mg of the sample cut from the sheet were equilibratedat ambient conditions, and then subjected to heating from 30° C. to 500°C. at 10° C./min in a nitrogen atmosphere. TABLE 1 Evaluation of thereaction ratio of PUP in DDGS/PU composites PUP DDGS Weight lossreaction Samples percentage % ^(a) % ratio ^(b) 1-DDGS 100 16.5 ± 0.1  —2-DP25 75 10.0 ± 0.2  92.7 3-DP30 70 9.1 ± 0.2 95.1 4-DP40 60 7.2 ± 0.198.4 5-DP50 50 6.1 ± 0.0 98.7 Average — — 96.2 ± 2.8^(a) calculated from the addition amount of PUP.^(b) calculated on the base of that corn oil content was hypothesized tobe 10.9 wt. %.

Results and Discussion.

FTIR spectra of castor oil, MDI, and PU prepolymer (PUP) are shown inFIG. 2. Two new peaks in the spectrum of PUP at 1724 and 1704 cm⁻¹ wereassigned to the stretching of C═O in urethane group, and a new peak at1522 cm⁻¹ was assigned to the combination of in-plane bending of N—H andstretching of C—N in urethane group. It can be concluded that urethanegroups have been formed, indicating a successful synthesis.

Soxhlet Extraction.

The weight loss of extracted samples is shown in Table 1.Toluene-soluble components in the DDGS were 16.5% as shown in Table 1.The toluene-soluble components are mainly comprised of corn oil andnon-corn oil fraction. Because corn oil would not react withdiisocyanate groups due to the chemical structure of corn oil, the cornoil was extracted from the DDGS/PU composites and was the main weightlost from the samples. The non-corn oil fraction contained a part ofalcohols, acids and amides according to the composition analysis(Biswas, S.; Staff, C. J. Cereal Sci. 2001, 33, 223) and would reactwith PUP in the composites. The existence of the non-oil fractionationmade it difficult to calculate the actual corn oil content in the DDGSon the basis of weight loss during extraction. According to the studiesreported in the literatures (Belyea, R. L.; Rausch, K. D.; Tumbleson, M.E. Bioresource Technol. 2004, 94, 293; Shukla, R.; Cheryan, M. Ind.Crops Prod. 2001, 13, 171), the corn oil content in DDGS generallyranged from 10.9 to 13 wt. %. If 13 wt. % was selected as the corn oilcontent, the calculated average reaction ratio would be 100.3%, furtherindicating the actual corn oil content in the DDGS was lower than 13 wt.%. The PUP reaction ratio was calculated on the basis of corn oilcontent as 10.9 wt. % in this study. As shown in Table 1, the averagereaction ratio of PUP reached as high as 96.2%, suggesting reactionratio was very high.

Mechanical properties of the distillers' dried grains withsolubles-polyurethane (DDGS-PU) composite are shown in Table 2. TABLE 2Mechanical properties of DDGS-PU composites PU DDGS Sample (DDGS-PUcontent content Toughness composites) (%) (%) σ_(b) ^(a) (MPa) ε_(b)^(b) (%) E ^(c) (MPa) (MPa) DP25 25 75 11.6 ± 0.0 5.2 ± 0.2 249 ± 7  44± 3 DP30 30 70 13.3 ± 0.7 6.2 ± 0.2 273 ± 23  65 ± 21 DP40 40 60 15.7 ±1.1 8.6 ± 0.8 391 ± 40 103 ± 17 DP50 50 50 16.0 ± 1.0 13.8 ± 1.4  312 ±38 148 ± 24^(a) σ_(b) strength at break,^(b) ε_(b) elongation at break,^(c) E is Young's modulus at 0.5-2%.

The toughness, strength at break and elongation at break of the DDGS-PUcomposites were increased with the content of PU under the presentexperimental conditions. As a control, DDGS without adding of PU cannotbe processed into sheets. This indicates polyurethane can efficientlyimprove the mechanical properties of the composite.

The mechanical properties of wet (immersed in water) DDGS/PU compositeswere also shown in Table 3. With an increase of PU content from 25 to 50wt. %, the water uptake was reduced and ranged from 27.5 to 5.3 wt. %,suggesting the PU component improved the water resistance of the DDGS/PUcomposites. After immersion in water for 24 h, all composites still wereflexible, although the strength of all composites decreased compared tothat of dried samples. As shown in Table 3, the strengths in the wetstate of the composites also were improved with the increasing PUcontent, further suggesting that polyurethane improved the waterresistance of DDGS-based materials. TABLE 3 Properties of wet DGGS/PUcomposites Samples Water uptake (%) σ_(b) (MPa) ε_(b) (%) DP25 27.5 ±0.7 2.5 ± 0.2 34 ± 3 DP30 27.2 ± 1.8 3.0 ± 0.2 47 ± 3 DP40  8.1 ± 0.57.0 ± 0.2 27 ± 2 DP50  5.3 ± 0.3 8.9 ± 0.4 31 ± 3

The visco-elastic property of the DP30 composite as evaluated throughDMA is shown in FIG. 3 and the related results for other DDGS-PUcomposites are shown in Table 4. TABLE 4 DMA results of DDGS/PUcomposites Samples T(tan δ) (° C.) DP25 35.3 ± 0.4 DP30 35.7 ± 0.6 DP4041.2 ± 1.0 DP50 44.4 ± 0.2 Extracted DP25 45.8 ± 0.5 MCPU 43.9 ± 0.2

The T_(g) of DP30 was 41° C. Its storage modulus was 1.7 GPa at 25° C.and 150 MPa at 60° C. Hence, the composite was tough and strong at roomtemperature. An image of DDGS/PU composites containing 44% of PU isshown in FIG. 4A. An image and schematic representation of a containermade from DP30 are shown in FIG. 4B and FIG. 4C, respectively.

Weight loss versus temperature curves of MCPU, DP25, DP50 and DDGS areshown in FIG. 5. There are two stages in the decomposition of MCPU (FIG.5, MCPU), one is from 270° C. to 350° C., and the other is from 350° C.to 500° C. At 500° C., the MCPU had the quickest degradation of the allsamples, implying that the polyurethane has less thermal resistance atthis temperature. Owing to the improvement of thermal stability for thecross-linked DDGS/PU composites, the residues content of both DP25 andof DP50 at 500° C. were higher than that of the pure PU sample. Becausethe PU components in the DDGS/PU composites had lower thermal resistanceat 500° C., the composites containing high amount of PU component wereeasily decomposed and the residual content decreased. This is the reasonwhy the residue content of DP50 at 500° C. was lower than that of DP25.In FIG. 5 (DDGS curve), moisture evaporation led to the weight loss ofDDGS from 25° C. to 140° C. and corn oil evaporation resulted in theweight loss of DDGS from 140° C. to 240° C.

Further embodiments of processes for preparing compositions that can beprepared as products, such as but not limited to furniture, trays,sheets and containers are represented in FIG. 6. Castor oil or soy oilor other vegetable/plant oils-based polyols can be used. The polyols aremixed with MDI to prepare active prepolymer. The process is costeffective because the reaction can be done in melt/liquid state. Theprepolymer, DDGS and fiber/organo-clay/fiber and organo-clay can bemixed in an extruder. The extruded material on further injection orcompression molding can result various shaped articles such asfurniture, tray, pot, container, sheet etc. These articles are likely tobe tough and water-resistant.

Preparation of the corn fiber-enforced DDGS-PU composites and the ageingproperties of the DDGS-PU composites.

Preparation of the DDGS-CS-PU composites.

Method: Corn stovers (CS) were obtained from Farm # 3660, Meridian Road,Mich. The corn stovers include stalks, leaves, no ears and no roots. TheCS were palletized in a granulator (B.T.P. Granulator, Granulator Div.Berlin, Conn.) and passed through a screen (2.7 mm mesh diameter) forpreparing CS powder. DDGS powder (60%) and corn stovers (CS, 15%) powderwere dried at 90° C. for four hours. The dried powder and polyurethaneprepolymer (PUP, 25%) were extruded in the DSM mini extruder. Theextrudates were compression-molded at 100° C. for 10 min. The sample wasnamed as: DDGS 60%-CS 15%-PU 25%. The samples were cut into rectangularsample for tensile testing.

Results: Mechanical properties of the DDGS-PU composites are shown inTable 5. TABLE 5 Mechanical properties the composites StrengthElongation at break at break E′ (25° C.), Samples (MPa) (%) (GPa) DDGS60%-CS 15%- 18.3 ± 1.6 2.5 ± 0.5 2.2 ± 0.2 PU 25% DDGS 75%-PU 25% 11.6 ±0.0 5.2 ± 0.2 1.2 ± 0.2

DDGS (60%)-CS (15%)-PU (25%) showed higher strength (18.3 MPa) than thatof DDGS (75%)-PU (25%) (11.6 MPa). The storage modulus of the formersample (2.2 GPa) was also much higher than that of the later sample (1.2GPa).

Conclusions: The stiffness and strength of the DDGS -based materialswere improved after incorporation of 15% of corn fiber.

Properties of the Composites After Ageing Treatment (Relative HumidityTreatment)

Method: Samples sheets (DDGS 60%-CS 15%-PU 25% and DDGS 75%-PU 25%) wereequilibrated at a given RH % for 1 month. The weight difference beforeand after the treatment was calculated. The storage modulus at 25° C.[E′ (25° C.)] was tested.

Results: Effects of RH % on the weight difference for the composites(DDGS 60%-CS 15%-PU 25%, DDGS 75%-PU 25%) are shown in FIG. 7. At 23%RH, both two samples lost moisture due to low relative humiditycondition. At 52% and 75% RH, the two composite samples showed a weightincreasing trend due to absorption of moisture from outside. With anincrease of RH values, the two samples will absorb more moisture. DDGScontains about 13 wt. % of corn oil, which can increase the hydrophobicproperties of the DDGS. DDGS can be considered more hydrophobic thancorn fiber because of the presence of corn oil in DDGS. At a given RHvalue as shown in FIG. 7, DDGS 75%-PU 25% would absorb less moisturecontent than DDGS 60%-CS 15%-PU 25%.

Effects of RH % on the storage modulus at 25° C. for the composites areshown in FIG. 8. The E′ (25° C.) decreased with an increase of RH value.This indicates that the materials are sensitive to moisture. At a givenRH value, the DDGS 60%-CS 15%-PU 25% showed much higher E′ (25° C.) thanthat of DDGS 75%-PU 25%, indicating that corn fiber significantlyimproved the stiffness of the composite. Conclusion: The composites aresensitive to moisture. Corn fiber significantly improved the stiffnessof the composite

Effects of microwave oven treatment on the properties of the composites.

Method: composites samples were first weighed (W1) and put into amicrowave oven (Emerson, MW8625, 600W, Emerson Radio Corp. Parsippany,N.Y., USA) at the “reheat” function. After a given time, samples weretaken out and weighed again (W2). Weight loss (%) was calculated usingthe following equation:Weight loss (%)=(W1−W2)/W1×100

A digital camera was used to take the image of the surface of thesamples.

Results: Properties of the DDGS 75%-PU 25% samples after microwave oventreatment are shown in Table 6. TABLE 6 Properties of the DDGS 75%-PU25% samples after microwave oven treatment Time (min) Weight loss %Surface Smell 0 0.0 Smooth A little 5 2.5 Burned Strong 10 5.1Burned/black Very strong

After the microwave oven treatment for 5 or 10 min, DDGS 75%-PU 25%showed burned surfaces and weight loss because the sample containedmoisture. The smell of the sample also became strong after the microwaveoven treatment. Conclusions: The DDGS -PU materials cannot resistmicrowave oven treatment because DDGS contains moisture and is easy tobe degraded at high temperature.

Ageing treatment in soil.

Methods: DDGS 75%-PU 25% and DDGS 60%-CS 15%-PU 25% composites were putin to soil for ageing. One month later, the samples were taken out andinspected by vision.

Results: The water up-take of the composites aged in soils that weretaken out after one month is shown in Table 7 and the images are shownin FIG. 9A and FIG. 9B. FIG. 9A illustrates DDGS 75%-PU 25% and FIG. 9Billustrates DDGS 60%-CS 15%-PU 25%. TABLE 7 Properties of the DDGS-PUcomposites aged in soil for one month Samples Water uptake (%) DDGS60%-CS 15%-PU 25% 57.2 ± 0.5 DDGS 75%-PU 25% 24.2 ± 0.3

Properties of the DDGS-PU Composite Aged at Out-Door Conditions.

DDGS 75%-PU 25% and DDGS 60%-CS 15%-PU 25% composites were put and tiedon a wood board. The system was placed on the ground and exposed to outdoor environments (2 rain days and 3 snow days). Water uptake and thesurface properties of the composites were studied.

Results: The properties of the two composites are shown in Table 8.After exposed to out door conditions for 2 rain days and 2 snow days,the two samples absorbed water, indicating the materials were watersensitive. The storage modulus of the DDGS 60%-CS 15%-PU 25% was alsodecreased from the original value (2.2 GPa, in Table 5) to 1.4 GPa asshown in Table 8. Similarly the storage modulus of the DDGS 75%-PU 25%was also decreased from the original value (1.2 GPa, in Table 5) to 0.7GPa as shown in Table 8. TABLE 8 Properties of the DDGS-PU compositesexposed in out-door conditions Water uptake E′ (25° C.), Surface Samples(%) (GPa) properties DDGS 60%-CS 15%-PU 25% 21.5 ± 1.8 1.4 ± 0.2 SmoothDDGS 75%-PU 25% 17.3 ± 0.8 0.7 ± 0.3 Smooth

Conclusions: The composites will absorb water after aged at out-doorconditions, resulting in a decrease in the stiffness of the composites.

While the present invention is described herein with reference toillustrated embodiments, it should be understood that the invention isnot limited hereto. Those having ordinary skill in the art and access tothe teachings herein will recognize additional modifications andembodiments within the scope thereof. Therefore, the present inventionis limited only by the Claims attached herein.

1. A composition which comprises: (a) a dried particulate by-product ofstarch fermentation of a grain to produce ethanol; and (b) a polymerizedpolyurethane binder derived from a polyurethane prepolymer comprising areaction product of at least one polyol and at least one isocyanate, theby-product being present in an amount between about 20 and 90% by weightof the composition.
 2. The composition of claim 1, wherein the polyol isa plant oil-based polyol.
 3. The composition of claim 2, wherein theplant oil-based polyol is selected from the group consisting of castoroil, soybean oil, rapeseed oil and mixtures thereof.
 4. The compositionof claim 1, wherein the isocyanate is a diisocyanate selected from thegroup consisting of 4, 4′-methylenedi-p-phenyl diisocyanate (MDI),naphthalene 1,5-diisocyanate (NDI), toluene diisocyanate (TDI),hexamethylene diisocyanate (HDI), IPDI, H₁₂-MDI, tetramethylenediisocyanate, and mixtures thereof.
 5. The composition of claim 1,wherein the by-product is derived from corn.
 6. The composition of claim5, wherein the by-product is distiller's dried grains with solubles(DDGS ).
 7. The composition of claim 1, wherein the polyurethaneprepolymer was formed in the presence of an organometallic or aminecatalyst.
 8. The composition of claim 1, wherein the organometalliccatalyst is selected from the group consisting of tin (II)2-ethylhexanoate, tinbutyltin dilaurate, and stannous octoate.
 9. Thecomposition of claims 1, 2 or 5, wherein the composition was extruded.10. The composition of claims 1, 2 or 5, wherein the composition wasrapidly extruded and then molded under pressure at elevatedtemperatures.
 11. The composition of claims 1, 2 or 5, furthercomprising natural fibers and organo-clay.
 12. The composition of claim11, wherein the natural fibers are corn fibers.
 13. A process forproducing the composition as set forth in claims 1, 2 or 5, whichcomprises extruding a mixture of the prepolymer and the by-product at atemperature between about 25° C. and 80° C.
 14. The process of claim 13wherein in addition the composition is molded under pressure at elevatedtemperatures between 80° C. and 150° C.
 15. A process for producing acomposition comprising: (a) providing a polyurethane prepolymercomprising a reaction product of at least one polyol and at least oneisocyanate; (b) extruding a mixture of the polyurethane prepolymer and adried particulate by-product of starch fermentation of a grain toprovide an extrudate; and (c) molding the extrudate of step (b) to formthe composition, wherein the by-product is present in an amount betweenabout 20 and 90% by weight of the composition.
 16. The process of claim15, wherein the extrudate of step (b) is compression molded in step (d).17. A composition produced by the process of claim
 15. 18. Thecomposition of claim 17, wherein the composition is formed as a productselected from the group consisting of a piece of furniture, a tray, asheet, and a container.
 19. A process for producing a compositioncomprising: (a) providing a polyurethane prepolymer comprising areaction product of at least one polyol and at least one isocyanate; (b)providing natural fibers; (c) extruding a mixture of the polyurethaneprepolymer, the natural fibers, and a dried particulate by-product ofstarch fermentation of a grain to provide an extrudate; and (d) moldingthe extrudate of step (b) to form the composition, wherein theby-product is present in an amount between about 20 and 90% by weight ofthe composition.
 20. The process of claim 19, wherein the extrudate ofstep (b) is compression molded in step (d).
 21. The process of claim 19,wherein the extrudate of step (b) is injection molded in step (d).
 22. Acomposition produced by the process of claim
 19. 23. The composition ofclaim 22, wherein the composition is formed as a product selected fromthe group consisting of a piece of furniture, a tray, a sheet, and acontainer.